Therefore, this post will focus on the length of time to prepare without knowing whether you will have to take the LSAT more than once.

Different people have different ideas about this, but …

Your goal is to both be prepared for the LSAT and feel that you are prepared for the LSAT.

At the beginning of your LSAT prep (at least this is how the people in my LSAT prep courses experience it) you will find LSAT questions to be interesting, fun and exciting. Let’s give some credit to Law Services. They do a great job of constructing an interesting test.

During that initial period where you find LSAT prep interesting and exciting you will read the questions with more interest and make fewer reading and reasoning mistakes. (Remember that the LSAT is a test of “reading and reasoning” in context.) Sooner or later that period of interest and excitement will “wear off” and LSAT will become tedious. At the point that it becomes tedious, you will make more reading mistakes, etc.

Hence, I am not a fan of presuming long periods of LSAT preparation. You can always add time to your LSAT prep, but you can never subtract.
Conclusion: Start with a period of six to 12 weeks. You can always add time if necessary. In addition, you should try to do your LSAT prep when you are not in school. Remember, your job is to get the best grades that you can.